This invention relates to photonic technology for guiding surface-plasmon-polaritons, and more particularly relates to control of dispersion in surface-plasmon-polariton propagation.
There is increasing interest in the design of surface-plasmon-polariton (SPP) photonic and optoelectronic systems; the unique light guiding properties of such SPP-based systems, such as subwavelength guiding of nanoscaled light, provide opportunities for the realization of optical processing devices and systems not previously achievable. One fundamental challenge for such modern photonic systems is the desire, for many applications, to operate as a substantially perfect light-guiding system by supporting, over a large frequency bandwidth, subwavelength modes of small group velocity and small attenuation, both substantially devoid of frequency dispersion. With such operation, a temporally- and spatially-tiny wavepacket could propagate through a photonic device without changing shape and with only a slow and uniform decrease in size. But conventional photonic systems exhibit modal dispersion that disallows such performance and that results in, e.g., limitation of the achievable so-called ‘bandwidth-delay product’ of the system, whereby only non-ideal wavepacket propagation is achievable.
It has been proposed to achieve control of dispersion in a photonic system by employing, e.g., coupled geometric or gain-material resonances or nonlinearities in the system design. But such configurations are limited in their applicability to general photonic device arrangements and photonic applications, including SPP-based devices and applications. As a result, many important modern optical systems, in particular those requiring slow or stopped subwavelength light, can be implemented only with suboptimal, dispersion-limited operation.